Use of Waste Heat from a Data Center
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The first of three planned buildings containing Facebook’s servers has been constructed in Luleå. Each building covers about 28 000 square meters and the total power consumption of the servers is about 28 MW. In order to cool the servers a technique called evaporative cooling is used. This technique utilizes outdoor air and lowers the temperature, when required, using a fine mist of purified water. The cold climate in Luleå together with the effective cooling technique makes the data center one of the most efficient in the world with a PUE (Power Usage Effectiveness) of about 1.07.Despite the high efficiency, 100 percent of the electricity used in the servers is converted into heat which is currently mostly being wasted. Currently, only a small part of this heat is being used for heating the office space in the building. The objective of the project described in this report is to find suitable uses for a larger portion of this heat. Based on which concept could offer the greatest advantages it was decided to investigate how the heat could be transported and used for heating in a greenhouse located next to the data center.A layout for an external distribution system for the exhaust air from the data center to the greenhouse along with suitable insulation is proposed. Three options are considered regarding the distribution system inside the greenhouse. From these one is proposed based on which offers the lowest cost and the greatest simplicity of construction. The total material cost of the entire distribution system including ducts, insulation and fans is about 6 million SEK for the proposed layout.Based on the calculated amount of heat available from the data center at the dimensioning outdoor temperature in Luleå which is -32 °C, the greenhouse dimensions were chosen as 300 meters long and 20 meters wide. The exhaust air heat is then sufficient to maintain the dimensioning indoor temperature of 20 °C. The chosen greenhouse structure is one with a gable roof to maximize light transmission and to withstand high snow loads. In total the cost would be roughly 21.2 million SEK including a foundation that would correspond to about 9 million SEK.The annual heat demand in the selected greenhouse is calculated to be about about 4000 MWh. Supplying this amount of heat via the exhaust air distribution system compared to using district heating gives cost savings of roughly 1.5 million SEK annually, including operating costs of the fans in the former case. When using the exhaust air from the data center the only cost associated with heating is basically the electricity required by the 28 fans for air transport which corresponds to about 300 000 SEK annually. This figure includes continuous operation of the fans in order to supply heating during winter, cooling during summer and a constant supply of fresh air all year round.
Place, publisher, year, edition, pages
2013. , 105 p.
IdentifiersURN: urn:nbn:se:ltu:diva-47637Local ID: 52b8e8c0-9762-41ce-a9e9-046cdfe22b61OAI: oai:DiVA.org:ltu-47637DiVA: diva2:1020965
Subject / course
Student thesis, at least 30 credits
Mechanical Engineering, master's level
Validerat; 20130617 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved